As regards lip-gloss, the difference in density and viscosity between traditional products and the new products make the telescopic stick dispensers unusable and require a modification of the distribution and application means in order to fulfil the conditions of dosage, watertightness and protection of the product.
Liquid product dispensers already exist of the types that comprise a reservoir, an internal piston and an application nozzle, generally provided with a valve.
However, for marketing reasons, it is important to preserve, at least partly, the overall appearance of the traditional packaging in order to avoid an abrupt break with the make-up habits of the users. In particular, it seems essential to perpetuate the use of a rotary movement for delivering the product.
And yet, due to the fluidity of the product, resorting to such a movement poses mainly watertightness and dispensing problems.
It is necessary, mainly, to guarantee the hermetic seal of the dispenser using an end valve that does not have any kind of retention area in which a residual volume of the product would be at a risk of remaining and drying up.